Implantable paddle lead comprising compressive longitudinal members for supporting electrodes and method of fabrication

ABSTRACT

In one embodiment, a paddle-style lead for implantation in the epidural space, the paddle-style lead comprising: a paddle structure that comprises a frame of rigid material, the frame comprising first, second, and third longitudinal members, a distal linking portion that is mechanically coupled to the first, second, and third longitudinal members, and a proximal linking portion that is mechanically coupled to the first, second, and third longitudinal members; wherein a respective plurality of electrodes are provided for each of the first, second, and third longitudinal members, each plurality of electrodes being electrically coupled to conductors of a lead body; wherein the distal and proximal linking portions are adapted to permit compression of the first and third longitudinal members toward each other and to permit the second longitudinal member to move out of plane relative to the first and third longitudinal members when a compressive force is applied to the paddle.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/162,596, filed Mar. 23, 2009, which is incorporated herein byreference.

TECHNICAL FIELD

The present application relates to an epidural stimulation lead, and inparticular, to an epidural stimulation lead adapted for percutaneousinsertion.

BACKGROUND

Application of specific electrical fields to spinal nerve roots, spinalcord, and other nerve bundles for the purpose of chronic pain controlhas been actively practiced since the 1960s. While a preciseunderstanding of the interaction between the applied electrical energyand the nervous tissue is not fully appreciated, it is known thatapplication of an electrical field (or stimulation) to spinal nervoustissue (i.e., spinal nerve roots and spinal cord bundles) caneffectively mask certain types of pain transmitted from regions of thebody associated with the stimulated tissue. More specifically, applyingparticularized electrical energy to the spinal cord associated withregions of the body afflicted with chronic pain can induce paresthesia,or a subjective sensation of numbness or tingling, in the afflictedbodily regions. This paresthesia can effectively mask the transmissionof non-acute pain sensations to the brain.

Successful pain management and the avoidance of stimulation inunafflicted regions necessarily require that the applied electric fieldor stimulation be properly positioned longitudinally along the dorsalcolumn. Positioning of an applied electrical field relative to aphysiological midline is also important.

Nerve fibers relating to certain peripheral areas extend between thebrain and a nerve root along the same relative side of the dorsal columnas the corresponding peripheral areas. Pain that is concentrated on onlyone side of the body is “unilateral” in nature. In contrast, pain thatis present on both sides of a patient is “bilateral.” To addressunilateral pain, electrical energy may be applied to neural structureson the side of a dorsal column that directly corresponds to a side ofthe body subject to pain. Accordingly, bilateral pain is typicallytreated through either an application of electrical energy along apatient's physiological midline or an application of electrical energythat transverses the physiological midline.

The applied electric field is commonly delivered through electrodespositioned external to the dura layer surrounding the spinal cord. Theelectrodes are typically carried by two primary vehicles: percutaneousleads and laminotomy leads.

Percutaneous leads commonly have a circular cross-section (typically inthe range of 0.05 inches) and three or more, equally-spaced ringelectrodes. Percutaneous leads are typically placed above the dura layerof a patient using a Touhy-like needle. For insertion, the Touhy-likeneedle is passed through the skin, between desired vertebrae, to openabove the dura layer. For unilateral pain, percutaneous leads arepositioned on a side of a dorsal column corresponding to the “afflicted”side of the body, as discussed above, and for bilateral pain, a singlepercutaneous lead is positioned along the patient midline (or two ormore leads are positioned on each side of the midline). Because of theirrelatively small dimensions, percutaneous leads typically are implantedwith a less-invasive method than used for laminotomy leads. Furthermore,a user has the ability to create a large variety of electrode arraypatterns by using a plurality of leads.

In contrast, laminotomy leads have a paddle configuration and typicallypossess a plurality of electrodes (for example, two, four, eight, orsixteen) arranged in one or more columns. The exposed surface area ofthe plurality of electrodes is commonly confined to only one surface ofthe laminotomy lead, thus facilitating a more focused application ofelectrical energy.

Laminotomy leads are typically implanted transversely centered over thephysiological midline of a patient. In such position, multiple columnsof electrodes are well suited to address both unilateral and bilateralpain, where electrical energy may be administered using either columnindependently (on either side of the midline) or administered using bothcolumns to create an electric field which traverses the midline.

A multi-column laminotomy lead usually enables reliable positioning of aplurality of electrodes, and in particular, a plurality of electrodecolumns that do not readily deviate from an initial implantationposition. Furthermore, they are capable of being sutured in place. So,there is less migration in the operating environment of the human body.Thus, they typically offer greater stability than percutaneous leads.

Given the relative larger dimensions of conventional laminotomy leads, asurgical procedure is usually required for implantation. The surgicalprocedure, or partial laminectomy, requires the resection and removal ofcertain vertebral tissue and often a portion of the vertebra to allowboth access to the dura and proper positioning of a laminotomy lead.

When selecting whether to use percutaneous leads or a laminotomy lead,therefore, the surgeon balances the risks of a more invasive surgicalprocedure against the advantages of using a laminotomy lead.

SUMMARY

In one embodiment, a paddle-style lead for implantation in the epiduralspace through an insertion tool, the paddle-style lead comprising: alead body; a plurality of conductors extending from a proximal portionof the lead body to a distal portion of the lead body; a plurality ofterminals that are electrically coupled to the plurality of terminals;and a paddle structure that comprises a frame of rigid material, theframe comprising first, second, and third longitudinal members, a distallinking portion that is mechanically coupled to the first, second, andthird longitudinal members, and a proximal linking portion that ismechanically coupled to the first, second, and third longitudinalmembers; wherein a respective plurality of electrodes are provided foreach of the first, second, and third longitudinal members, eachplurality of electrodes being electrically coupled to conductors of theplurality of conductors; wherein the distal and proximal linkingportions are adapted to permit compression of the first and thirdlongitudinal members toward each other and to permit the secondlongitudinal member to move out of plane relative to the first and thirdlongitudinal members when a compressive force is applied to the paddle.

The foregoing has outlined rather broadly certain features and/ortechnical advantages in order that the detailed description that followsmay be better understood. Additional features and/or advantages will bedescribed hereinafter which form the subject of the claims. It should beappreciated by those skilled in the art that the conception and specificembodiment disclosed may be readily utilized as a basis for modifying ordesigning other structures for carrying out the same purposes. It shouldalso be realized by those skilled in the art that such equivalentconstructions do not depart from the spirit and scope of the appendedclaims. The novel features, both as to organization and method ofoperation, together with further objects and advantages will be betterunderstood from the following description when considered in connectionwith the accompanying figures. It is to be expressly understood,however, that each of the figures is provided for the purpose ofillustration and description only and is not intended as a definition ofthe limits of the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a is a top view of a laminotomy lead according to one inventiveembodiment.

FIG. 1 b is a top view of the laminotomy lead of FIG. 1 a in a second orinsertion configuration.

FIG. 1 c is a detailed view of an electrode of the lead shown in FIG. 1a.

FIG. 2 is an isometric view of a laminotomy lead according to anotherinventive embodiment.

FIG. 3 is an isometric view of a laminotomy lead according to anotherinventive embodiment.

FIG. 4 is an isometric view of a laminotomy lead according to anotherinventive embodiment.

FIG. 5 a is an isometric view of two percutaneous leads which could beincorporated into the laminotomy lead kits of FIGS. 5 b-5 d, FIG. 6, andFIG. 7.

FIG. 5 b is an isometric view of a laminotomy lead kit according to oneinventive embodiment.

FIG. 5 c is an isometric view of a laminotomy lead kit according toanother inventive embodiment.

FIG. 5 d is an isometric view of a laminotomy lead kit according toanother inventive embodiment.

FIG. 6 is an isometric view of a laminotomy lead kit according toanother inventive embodiment.

FIG. 7 a is an isometric view of a laminotomy lead kit according toanother inventive embodiment.

FIG. 7 b is a detailed isometric view of a distal portion of laminotomylead kit of FIG. 7 a.

FIG. 8 a is a plan view of a proximal end of a lead.

FIG. 8 b depicts an implantable pulse generator coupled to a laminotomylead according to one inventive embodiment.

DETAILED DESCRIPTION

Some representative embodiments are directed to flexible paddlestimulation leads for percutaneous implantation wherein the flexiblepaddle stimulation leads have a distal end portion which is capable ofexpanding from an insertion configuration to an implantationconfiguration. There are also disclosed various methods of inserting aflexible paddle stimulation lead into a body, the methods includepercutaneously positioning a tubular member adjacent to a site toreceive therapeutic stimulation, compressing a lateral dimension of adistal end portion of an implantable lead, inserting the distal endportion into a tubular member, urging the distal end portion through thetubular member, expanding the lateral dimension of the distal endportion such that the distal end portion is placed to delivertherapeutic stimulation. In certain embodiments, there may be a systemcomprising a flexible paddle stimulation lead and insertion tools forpercutaneously implanting the flexible paddle portion adjacent to astimulation site.

FIG. 1 a is a plan view of a flexible paddle 100 of a laminotomy lead102. The lead 102 is adapted for implantation into the epidural space ofa patient for stimulation of fibers of the dorsal column of a patient'sspinal cord. Lead 102 could alternatively be employed for any othertissue stimulation application. The lead 102 comprises a lead body 103having a proximal end (not shown) and a distal end portion, such as theflexible paddle 100. The lead body 103 comprises a plurality ofconductors (not shown) embedded or otherwise contained within insulativematerial.

The flexible paddle 100 comprises a longitudinal frame 104 and elasticmembrane 106 disposed across the interior surface area defined by frame104. The elastic membrane 106 has a first side or face 108 and a secondside (not shown). A plurality of electrodes 110 are positioned on thefirst face 108 of the elastic membrane 106. A plurality of conductingelements 112 are disposed on the paddle to electrically couple theplurality of electrodes 110 to conductors (not shown) contained orembedded within the insulative material of lead body 103. The conductorsare connected to terminals (not shown) positioned at the proximal end ofthe lead body 103.

Paddle 100 is adapted to deform to permit paddle 100 to be insertedthrough the lumen of a needle or suitable insertion tool into theepidural space of a patient. Such deformation permits paddle 100 to beimplanted within the epidural space of a patient without requiring apartial laminectomy. After paddle 100 reaches the distal end of theneedle or insertion tool, paddle 100 is adapted to resume its originalshape thereby permitting the electrodes 110 to be positioned in anadvantageous manner for spinal cord stimulation. As illustrated in FIG.1 a, the flexible paddle 100 is shown in its fully expanded or relaxedstate.

FIG. 1 b is a plan view of the flexible paddle 100 in an elongated orinsertion configuration.

Frame 104 of paddle 100 is adapted for such deformation by including afirst longitudinal portion 118, a second longitudinal portion 120, adistal biasing or spring member 122 and a proximal spring member 124. Asillustrated, the distal spring member 122 may be shaped similar to a “V”having the rounded tip portion 126 and two arms 128 a and 128 b. Theproximal spring member 124 may also be shaped in a V, but with adifferent orientation. A tip portion 129 of the proximal spring member124 points toward the proximal direction. In certain embodiments, frame104 is formed using a rigid or high durometer, biocompatible, biostablepolymer. As used herein, the term “rigid” refers to the degree ofdeformability of frame. That is, frame 104 tends to change itsconfiguration without undergoing appreciable deformation. In contrast,membrane 106 deforms or stretches when paddle 100 changes states.Examples of suitable polymers for frame 104 include polyimide,polyetheretherketone (PEEK), polyether-ketone ketone (PEKK), and liquidcrystal polymer (LCP). In some alternative embodiments, all of the frame104 or selected portions thereof (e.g., spring members 122 and 124) maybe made from or include metallic material.

In the fully relaxed state, springs 122 and 124 maintain longitudinalportions 118 and 120 at a distance apart as shown in FIG. 1 a. In oneembodiment, during an implantation procedure, paddle 100 is insertedinto the lumen of an insertion tool and spring 122 contacts the innersurface of the tool defined by the lumen. The contact force tends to“pinch” the spring member thereby providing a compressive force to thespring member. The compression of spring 122, in turn, bringslongitudinal portions 118 and 120 closer together as shown in FIG. 1 b.Spring 124 is also compressed due to its mechanical coupling to members118 and 120.

The elastic membrane 106 is preferably fabricated from a low durometerand elastic biocompatible material, such as CARBOSIL® (a siliconeurethane copolymer) or another elastomer. The elastic nature of membrane106 permits membrane 106 to stretch when force is applied to or removedfrom paddle thereby causing paddle 100 to change shapes. Paddle 100 ispreferably adapted such that elastic membrane 106 is stretchedlongitudinally when paddle 100 is in the state shown in FIG. 1 b.Alternatively, paddle 100 may be adapted such that elastic membrane 106is stretched in latitudinal manner when paddle 100 is in the state shownin FIG. 1 a.

Electrodes 110 and conducting elements 112 are preferably fabricated bydepositing or otherwise providing conductive material on the elastomermaterial. In one embodiment, the conductive traces are built upon on a0.001″ or 0.002″ film of LCP. The LCP is also adhered to a substrateusing a temporary adhesive. Selected portions of the LCP film are cutaway and removed leaving behind on LCP material where the body of thetraces and electrodes are disposed. The remaining LCP material withtraces and electrodes is laminated or coated with the appropriateelastomer. The electrodes are then exposed using a TEA laser.

In another embodiment, the conductive traces are produced directly onthe elastomer by using ink jet technology or by using conventionalphotolithographic methods but applying them to an elastomer substrate ina stretched state. Once the metallization is complete along withplate-up the elastomer substrate is allowed to return to its naturaldimensions resulting in conductive compression. In this embodiment, itis preferred to obtain superior metal to polymer adhesion.

Stretching of membrane 106 is problematic for conventional medicaldevice fabrication techniques. Specifically, metallic material depositedor otherwise applied to known biocompatible elastomers may tend todelaminate or otherwise separate from such material when the elasticmaterial is stretched. Electrodes 110 and conducting elements 112 arepreferably implemented to substantially prevent or eliminate suchseparation from occurring by adapting electrodes 110 and conductingelements 112 to stretch in a corresponding manner to stretching ofelastomer 106.

In certain embodiments, the conducting elements 112 are disposed on thepaddle surface in a manner that elements 112 comprise a plurality ofcurves which allow the conducting elements 112 to “stretch” as paddle100 changes states between the states shown in FIGS. 1 a and 1 b. Eachconducting element 112 is formed using a continuous trace of metallicmaterial applied to membrane 106. In a preferred embodiment, thecontinuous trace repetitively curves or winds in alternative directionsin a serpentine manner. The alternating shape of the respective metaltraces permits conducting elements 112 to elongate as the frame 104 andmembrane 106 changes states. The width of the curves of the continuoustrace may be uniform or may vary along the length of paddle 100.

Electrodes 110 are also preferably fabricated to substantially preventseparation of electrodes 110 from elastic membrane 106. FIG. 1 c is adetail view of one embodiment of two electrodes 130 a and 130 b whichare members of the plurality of electrodes 110 (FIGS. 1 a and 1 b).Electrodes 130 a and 130 b are formed using a continuous trace ofmetallic material applied to membrane 106. The continuous tracerepetitively curves or winds in alternative directions in a serpentinemanner. The alternating shape of the respective metal traces permitselectrodes 130 a and 130 b to elongate as the frame 104 changes states.The width of the curves of the continuous trace may be uniform along thelength of electrodes 130 a or may vary as desired to effect the chargetransfer characteristics of the electrodes. Two lateral portions 132 and134 of two conducting elements are illustrated branching off from thecurved portions of the conducting elements 112.

In some embodiments, when paddle 100 is to be implanted, the frame 104and the elastic membrane 106 may be elongated with a stylet to assume aninsertion configuration as illustrated in FIG. 1 b. As the longitudinalbody is elongated, the lateral profile of the frame 104 decreases whichallows the longitudinal body to be inserted into an appropriateinsertion tool (not shown). When the frame 104 exits the insertion tooland the stylet no longer elongates the frame 104, the spring members 122and 124 are no longer subject to the compressive forces and can expandto a predetermined distance as illustrated in FIG. 1 a. The electrodes110 may then be positioned within the epidural space in a manner that issimilar to an electrode spacing of a conventional paddle-style lead.

Paddle 100 may be placed within the epidural space of a patient usingany suitable epidural needle or other insertion tool. Examples ofsurgical implantation and insertion tools that can be utilized withpaddle 100 are described in U.S. Patent Application Publication No.20050288759, entitled “Method and Apparatus for Implanting an ElectricalStimulation Lead Using a Flexible Introducer,” and U.S. PatentApplication Publication No. 20050209667, entitled “Stimulation SensingLead Adapted for Percutaneous Insertion,” both disclosures are hereinincorporated by reference. Additionally, an expandable paddle may beintroduced through a suitable tool while the paddle is held within atube structure according to one representative embodiment. The tubestructure may be fabricated from a suitable polymer material. The wallthickness of the tube structure may preferably be relatively small(e.g., a few thousands of an inch). An embedded monofilament or finewire may be included within the wall to provide additional strength orrigidity to the tube structure. During introduction, the expandablepaddle structure is maintained in a compressed state by the wall of thetube structure. The surgeon may advance and steer the tube structurewithin the epidural space. Upon reaching the appropriate implantposition, the surgeon may withdraw the tube structure while leaving thepaddle in place. At this point, the paddle would expand due to itsstructural characteristics. Such a tube structure may also facilitateexplantation of a paddle structure if a surgeon deems removal of apreviously implanted paddle as medically appropriate. In an alternativeembodiment, the tubular structure may be integrated with the lead body.In this embodiment, the tubular structure may be retracted to expose thepaddle thereby permitting the paddle to expand. Likewise, uponexplantation, the tubular structure may be advanced to collapse thepaddle.

FIG. 2 is an isometric view of flexible paddle 200 for use with alaminotomy lead. The flexible paddle 200 comprises a frame 202 which maybe formed from a high durometer, biocompatible, biostable polymer, suchas PEEK or PEKK. As illustrated, the frame 202 comprises a firstlongitudinal member 204, a second longitudinal member 206, a distalspring member 208, and a proximal spring member 210. In certainembodiments, the proximal spring 210 may be coupled to a laminotomy leadconnector 212. In certain embodiments, the laminotomy lead connector 212couples to a female lamitrode connector (not shown) positioned on thedistal portion of a lead (not shown), although any suitable electricalconnections could be employed. When the laminotomy lead connector 212 iscoupled to the corresponding female laminotomy lead connector, anelectrical connection is possible between conductors in a lead body andconducting elements within the flexible paddle 200.

The first longitudinal member 204 and the second longitudinal member 206each have a first side or face 214, 216, respectively and a second sideor face (not shown). In certain embodiments, a first plurality ofelectrodes 218 may be positioned on the first face 214 of the firstlongitudinal member 204. Similarly, a second plurality of electrodes 220may be positioned on the first face 214 second face 216 of the secondlongitudinal member 206.

In some embodiments, electrodes 218 and 220 are formed using anink-jetting process using commercially available ink-jetting techology.The ink comprises gold particles that range from 2-10 nanometers in asolvent carrier with a small amount of lignan. When heated to 170° C.,the organics evaporate thereby leaving the nano gold particles to fuseto each other. To facilitate bonding of the gold particles to the PEEKsubstrate, a single mono-molecular layer of mercaptotrimethoxysilane orsimilar compound is employed. The mercapto or thio groups bond to goldon one side of the molecule while the silane portion of the moleculebonds to the PEEK surface (optionally modified by an oxygen plasma) onthe other side of the molecule. The jetted conductive pattern(s) arethen plated with suitable biocompatible materials, such as gold,platinum, platinum iridium, etc. using conventional electro-platingprocesses.

A plurality of conducting elements (not shown) electrically couple thefirst and second plurality of electrodes 218 and 220 to the laminotomylead connection 212. The conducting elements may be deposited orotherwise applied between respective layers of insulative material offrame 202. In other embodiments, the conducting elements may be tracesdisposed on the second face of members 204 and 206 and covered by a thinlayer of insulative material. Vias may be employed during paddlefabrication to permit electrical coupling between the conductingelements and electrodes 218 and 220.

In an alternative embodiment, electrodes 218 and 220 and suitableelectrical conducting elements may be formed on one or more layers offlex film laminated or otherwise attached to frame 202.

In certain embodiments, a thin layer of elastic material may be providedbetween the first longitudinal member 204 and the second longitudinalmember 206 to prevent fibrous growth of tissue between the longitudinalmembers after the paddle 200 has been implanted.

In certain embodiments, the distal spring member 208 may be shaped sothat when the tip portion 222 of the spring member encounters an innerwall of a tubular insertion tool (not shown), the contact force tends to“pinch” the spring member thereby providing a compressive force to thespring member. As illustrated, the spring member 208 may be shapedsimilar to a “V” having a rounded tip portion 222 and two arms 224 a and224 b.

In certain embodiments, the proximal spring member 210 may also beshaped into a “V” shape having a vertex or tip portion 226. In certainembodiments, the tip portion 226 of the proximal spring member 210points toward the proximal direction. This allows the proximal springmember 210 to collapse in situations where explantation of the paddle isnecessary.

Thus, when the flexible paddle 200 is to be implanted, the distal springmember 208 can be inserted into a tubular insertion tool (not shown).The insertion of the spring member 208 will pinch the arms 224 a and 224b as they enter the tubular insertion tool. The pinching will place acompressive force on the arms 224 a and 224 b, which will cause themembers to move towards each other. In turn, the longitudinal members204 and 206 will laterally compress towards each other. This compressionreduces the lateral profile of the flexible paddle 200 which allows theflexible paddle 200 to be inserted into an appropriate implantationtool. When the flexible paddle 200 exits the implantation tool, thespring members 208 and 210 are no longer subject to the compressiveforces imposed by the tubular insertion tool and can expand apart. Theelectrodes 218 and 220 may then be positioned within the epidural spacein a manner that is similar to an electrode spacing of a conventionalpaddle-style lead.

FIG. 3 is an isometric view of another embodiment of a flexible paddle300 of a distal end of a laminotomy lead according to one inventiveembodiment. The flexible paddle 300 may comprise a frame 302 which maybe formed from a high durometer, biocompatible, biostable polymer, suchas PEEK, PEKK, or LCP.

As illustrated, the frame 302 comprises a first longitudinal Member 304,a second longitudinal member 306, a middle longitudinal member 308, adistal spring member 310, and a proximal spring member 312. In certainembodiments, the proximal spring member 312 may be coupled to alaminotomy lead connector 314. In certain embodiments, the laminotomylead connector 314 couples to a female lamitrode connector (not shown)positioned on the distal portion of a lead body (not shown), althoughany suitable electrical connections could be employed.

The first longitudinal member 304, the second longitudinal member 306,and the middle longitudinal member 308 each have a first side or face316, 318, and 320 respectively and a second side or face (not shown). Incertain embodiments, a first plurality of electrodes 322 may bepositioned on the first face 316 of the first longitudinal member 304.Similarly, a second plurality of electrodes 324 may be positioned on thefirst face 318 of the second longitudinal member 306 and a thirdplurality of electrodes 326 may be positioned on the first face 320 ofthe middle longitudinal member 308. The electrodes of the first, second,and third plurality of electrodes 322, 324, and 326 may be formed in ansuitable manner including the process described above in regard topaddle 200 of FIG. 2.

A plurality of conducting elements (not shown) electrically couple thefirst, second, and third plurality of electrodes 322, 324, 326 and tothe laminotomy lead connector 314. In certain embodiments, theconducting elements may be provided within the insulative material ofthe respective longitudinal member 304, 306 and 308. In otherembodiments, the conducting elements may be traces deposited orotherwise provided on the second face of longitudinal member 304, 306,and/or 308.

In other embodiments, a flex-circuit may be employed to provideelectrodes and the conducting elements where the flex-circuit isattached or laminated to the PEEK, PEKK, or LCP material of frame 302.

In certain embodiments, a thin elastic layer may be positioned betweenthe longitudinal members to prevent a fibrous growth of tissue betweenthe longitudinal members of the flexible paddle 300 after the flexiblepaddle 300 has been implanted.

In certain embodiments, the distal spring member 310 may be shaped sothat when a tip portion 328 of the spring member encounters an innerwall of a tubular insertion tool (not shown), the contact force tends to“pinch” the spring member thereby providing a compressive force to thespring member. As illustrated, the distal spring member 310 may beshaped similar to a “V” having a rounded tip portion 328 and two arms330 a and 330 b. In certain embodiments, two linkage members 332 a and332 b couple the middle longitudinal member 308 to the distal springmember 310. In some embodiments, there may be a detent formed at theintersection of the linkage members 332 a-332 b and the spring arms 330a-330 b. The detent biases the linkage members to deflect in apredetermined direction when the spring arms 330 a-330 b are compressed.

In certain embodiments, the proximal spring member 312 may also comprisearm members 334 a-334 b which are coupled together to form a “V” shape.In some embodiments, the vertex of the V shape of the proximal springmember 312 points toward the proximal direction. This allows theproximal spring member 312 to collapse in situations where explantationof the paddle is necessary. In certain embodiments, two linkage members336 a and 336 b couple the middle longitudinal member 308 to theproximal spring member 312. In some embodiments, there may be a detentformed at the intersection of the linkage members 336 a-336 b and thespring arms 332 a-332 b. The detent biases the linkage members todeflect in a predetermined direction when the spring arms 334 a-334 bare compressed.

When the flexible paddle 300 is implanted, the distal spring member 310can be inserted into a tubular insertion tool (not shown). The insertionof the spring member 312 will pinch the arms 330 a and 330 b together asthey enter the tubular insertion tool. The pinching will place acompressive force of the arms 330 a and 330 b, which will cause themembers to deflect towards each other. As the arms 330 a and 330 b beginto move, the linkage members 332 a and 332 b deflect out of the planeformed by the first longitudinal member 304 and the second longitudinalmember 306. The middle longitudinal member 308 is also carried out ofits position or plane by the movement of the linkage members 332 a and332 b. At the proximal end, the linkage members 336 a-336 b also allowthe middle longitudinal member 308 to move out of plane. Once the middlelongitudinal member is out of the plane, the longitudinal members 304and 306 are free to laterally compress towards each other. Thiscompression reduces the lateral width of the flexible paddle 300 whichallows the flexible paddle 300 to continue to be inserted through thetubular insertion tool. Although three longitudinal members are shownfor paddle 300, paddles having a greater number of longitudinal memberscan be implemented to allow the respective members to collapse togetherwith certain longitudinal members moving out of plane.

When the flexible paddle 300 exits the implantation tool, the springmembers 310 and 312 are no longer subject to the compressive forces ofthe tubular insertion tool and can expand to a predetermined distance.The expansion of the spring members allows the longitudinal members304-306 to follow and also expand while at the same time moving themiddle longitudinal member 308 back into its original plane. Theplurality of electrodes 322, 324, 326 may then be positioned within theepidural space in a manner that is similar to an electrode spacing of aconventional paddle-style lead.

FIG. 4 is an isometric view of another inventive flexible paddle 400 fora distal end of a laminotomy lead. The flexible paddle portion 400 maycomprise a frame 402 which may be formed from a high durometer,biocompatible, biostable polymer, such as PEEK or PEKK.

As illustrated, the frame 402 comprises a first longitudinal member 404,a second longitudinal member 406, a middle longitudinal member 408, adistal spring member 410, and a proximal spring member 412. In certainembodiments, the proximal spring member 412 may be coupled to alaminotomy lead connector 414. In certain embodiments, the laminotomylead connector 414 couples to a female lamitrode connector (not shown)positioned on the distal portion of a lead body (not shown), althoughany suitable electrical connections could be employed.

The first longitudinal member 404, the second longitudinal member 406,and the middle longitudinal member 408 each have a first side or face416, 418, and 420 respectively and a second side or face (not shown). Incertain embodiments, a first plurality of electrodes 422 may bepositioned on the first face 416 of the first longitudinal member 404.Similarly, a second plurality of electrodes 424 may be positioned on thefirst face 418 of the second longitudinal member 406 and a thirdplurality of electrodes 426 may be positioned on the first face 420 ofthe middle longitudinal member 408. In the illustrative embodiment, thethird plurality of electrodes 426 comprises three columns of electrodes.In other embodiments, there may only be one or two columns ofelectrodes. The electrodes of the first, second, and third plurality ofelectrodes may be formed using any suitable process including thedeposition process discussed in regard to paddle 200 of FIG. 2.

A plurality of conducting elements (not shown) electrically couple thefirst, second, and third plurality of electrodes 422, 424, 426 and tothe laminotomy lead connection 414. In certain embodiments, theconducting elements may be formed within layers of the insulativematerial of longitudinal member 404, 406 and 408. In other embodiments,the conducting elements may be traces provided on the second respectivefaces of longitudinal member 404, 406, and/or 408.

In certain embodiments, the distal spring member 410 may be shaped sothat when the spring member encounters an inner wall of a tubularinsertion tool (not shown), the contact force tends to “pinch” thespring member thereby providing a compressive force to the springmember. As illustrated, the spring member 410 may be shaped similar to a“V” having a vertex or rounded tip portion 428 and two arms 430 a and430 b.

In certain embodiments, the proximal spring member 412 may also comprisearm members 432 a-432 b which are coupled together to form a “V” shape.In some embodiments, a vertex 431 of the V shape of the proximal springmember 412 points toward the proximal direction. This allows theproximal spring member 412 to collapse in situations where explantationis necessary.

In certain embodiments, the middle longitudinal member 408 is coupled tothe distal spring member 410 close to the tip portion 428. The middlelongitudinal member 408 may also be coupled to the proximal springmember 412 close to the vertex 431 of the proximal spring member 412.Coupling the middle longitudinal member 408 to the spring members closeto their respective vertexes allows the spring arms to move freely withrespect to the middle longitudinal member. In turn, the firstlongitudinal member 404 and the second longitudinal member 406 are alsofree to move with respect to the middle longitudinal member 408.

When the flexible paddle 400 is implanted, the distal spring member 410can be inserted into a tubular insertion tool (not shown). The insertionof the distal spring member 410 will pinch its arm members 430 a and 430b together as they enter the tubular insertion tool. The pinching willplace a compressive force on the arm members 430 a and 430 b, which willcause the arm members to deflect towards each other. The movement of armmembers 430 a and 430 b will cause the longitudinal members 404 and 406to follow and laterally compress towards each other. The middlelongitudinal member 408 is in a different plane than the springs 410,412 and the longitudinal members 404 and 406. This positioning allowsthe longitudinal members 404 and 406 to compress with respect to eachother without interference from the middle longitudinal member 408. Thiscompression reduces the lateral width of the flexible paddle 400 whichallows the flexible paddle 400 to be inserted through an appropriateimplantation tool.

When the flexible paddle 400 exits the implantation tool, the springmembers 408 and 410 are no longer subject to the compressive forces ofthe tubular insertion tool and can expand to a predetermined distance.Similarly the longitudinal members 404 and 406 follow and also expandrelative to each other. The electrodes 418 may then be positioned withinthe epidural space in a manner that is similar to an electrode spacingof a conventional paddle-style lead.

According to other alternative inventive embodiments, a conversion kitmay be provided to stably position percutaneous leads within theepidural space in a manner that may have some of the benefits andcharacteristics of flexible laminotomy leads. FIG. 5 a illustrates thedistal end portion of two percutaneous stimulation leads 502 a and 502 beach having a plurality of stimulation electrodes 504 a and 504 b whichare coupled to conductors (not shown) running longitudinally within theleads 502 a and 502 b. For purposes of illustration only, the leads 502a and 502 b are shown with eight stimulation electrodes in eachplurality of stimulation electrodes 504 a-504 b. As will be appreciatedby those skilled in the art, any number of stimulation electrodes may beutilized as desired within the leads 502 a and 502 b. In thisillustrative embodiment, the pluralities of stimulation electrodes 504 aand 504 b are shown as band or ring electrodes. In certain embodiments,the stimulation electrodes 504 a and 504 b may be formed ofbiocompatible, conductive materials which do not develop a significantamount of oxide films, such as platinum and platinum-iridium, or otherconductive materials, metals or alloys known to those skilled in theart. An example of a suitable commercially available lead which could beused as stimulation leads 502 a-502 b is the Axxess® lead available formSt. Jude Medical Neuromodulation Division (Plano, Tex.).

Turning now to FIG. 5 b, there is one embodiment of an assembly or kit500 using the stimulation leads 502 a and 502 b. The assembly 500 maycomprise a frame 506 and a retention clip 508 to retain the stimulationleads 502 a-502 b together. The retention clip 508 may also facilitatethe removal of the assembly 500 from the epidural space if the leads 502a-502 b need to be explanted.

The frame 506 may comprise two longitudinal members 510 a and 510 b. Incertain embodiments, the longitudinal members 510 a-510 b may be tubularmembers fabricated from a relatively high durometer, biocompatible,biostable polymer. Examples of suitable polymers include PEEK, PEKK, andLCP. In certain embodiments, the tubular members may have internaldiameters which are sized to accommodate the external diameters of thestimulation leads 502 a-502 b such that the longitudinal members 510a-510 b can slide over the stimulation leads 502 a and 502 b,respectively. In certain embodiments, there may be a series of openingsor apertures 511 a-511 b which are configured to align with thestimulation electrodes 504 a-504 b of the stimulation leads 502 a-502 b.The apertures 511 a-511 b may be formed from ablating portions of thewalls of the longitudinal members 510 a-510 b with a suitable laser.When suitably assembled and aligned, the apertures 511 a-511 b may causethe field under the corresponding electrodes to be substantiallyunidirectional.

In certain embodiments, a primary spring or springs 512 couples to thelongitudinal members 510 a-510 b and maintains the longitudinal membersin a substantially parallel arrangement. In certain embodiments, theremay also be a distal end spring member 514, which may be configured toassist in the percutaneous placement of assembly 500. In the embodimentillustrated by FIG. 5 b, the primary spring 512 is a pair of leafsprings 516 a-516 b which act to bias the arms at a predetermineddistance apart. Other types of biasing may also be used for the primaryspring 512. As an example, in FIG. 5 c, there is illustrated anembodiment where a series of diamond springs 518 which bias thelongitudinal members 510 a-510 b at a predetermined distance. FIG. 5 dillustrates another example where the primary springs 512 of the frame506 are a series of O-rings 520 are used as biasing members to maintainthe longitudinal members 510 a and 510 b at a predetermined distance.

Turning back to FIG. 5 b, it can be seen that in certain embodiments,the distal spring member 514 may be shaped so that when the tip portion522 of the distal spring member encounters an inner wall of a tubularinsertion tool (not shown), the contact force tends to “pinch” thespring member thereby providing a compressive force to the springmember. As illustrated, the distal spring member 514 may be shapedsimilar to a “V” having a rounded tip portion 522 and two arms 524 a and524 b which couple to the longitudinal members 510 a and 510 b,respectively.

The primary spring 512 and distal spring 514 may also be made out ofsuch materials possessing a spring memory characteristic, such as PEEKor a suitable biocompatible metal. In some alternative embodiments, theprimary spring 512 and the distal spring 514 may be made from metalspring elements or a combination of PEEK and metal elements. Forinstance, in certain embodiments, the longitudinal members 510 a and 510b of the frame 506 and the primary spring 512 may be made from PEEK andthe distal spring 514 may be made from a biocompatible metal.

In certain embodiments, a thin elastic layer 526 may be positionedbetween the first longitudinal member 510 a and the second longitudinalmember 510 b to prevent a fibrous growth of tissue between thelongitudinal members after the assembly 500 has been implanted.

When the assembly 500 is to be implanted, the distal spring member 514can be inserted into a tubular insertion tool (not shown). The insertionof the spring member 514 will pinch the arm members 524 a and 524 b asthey enter the tubular insertion tool. The pinching will place acompressive force on the arm members 524 a and 524 b, which will causethe members to move towards each other. In turn, the longitudinalmembers 510 a and 510 b will follow the movement of the arm members 524a-524 b and laterally compress towards each other as the compressionforces overcome the biasing force of the primary spring(s) 512. Thiscompression reduces the lateral profile of the assembly 500 which allowsthe assembly to be inserted into an appropriate implantation tool. Whenthe assembly 500 exits the implantation tool, the spring members 512 and514 are no longer subject to the compressive forces imposed by thetubular insertion tool and can expand to a predetermined distance. Theassembly 500 and the associated electrodes 504 a and 504 b may thenpositioned within the epidural space in a manner that is similar to anelectrode spacing of a conventional paddle-style lead.

Turning now to FIG. 6, there is another embodiment of an assembly or kit600 using the stimulation leads 502 a and 502 b and a frame 602. Asillustrated, the frame 602 comprises a first longitudinal member 604, asecond longitudinal member 606, a distal spring portion 608, and aproximal spring portion 610. In certain embodiments, the proximal springportion 610 may be coupled to a support member 612. In certainembodiments, the support member 612 couples to the stimulation leads 502a and 502 b. In one embodiment, there may be one or more retaining clips613 to couple the support member 612 to the stimulation leads 502 a-502b. In certain embodiments, the frame 602 may be formed from a highdurometer, biocompatible, biostable polymer, such as PEEK, PEKK, or LCP.

The first longitudinal member 604 and the second longitudinal member 606each have a first side or face 614, 616, respectively and a second sideor face (not shown). In certain embodiments, a first plurality retainingclips (not shown) secures the leads to first face 614 of the firstlongitudinal member 604. Similarly, a second plurality of retainingclips (not shown) may be positioned on the first face 616 of the secondlongitudinal member 606 to secure the lead 502 b to the longitudinalmember 606.

In certain embodiments, a thin elastic layer 618 may be positionedbetween the first longitudinal member 604 and the second longitudinalmember 606 to prevent a fibrous growth of tissue between thelongitudinal members after the assembly 600 has been implanted.

In certain embodiments, the distal spring portion 608 may be shaped sothat when a tip portion 622 of the distal spring portion encounters aninner wall of a tubular insertion tool (not shown), the contact forcetends to “pinch” the distal spring portion thereby providing acompressive force to the distal spring portion. As illustrated, thedistal spring portion 608 may be shaped similar to a “V” having arounded tip portion 622 and two arms 624 a and 624 b.

In certain embodiments, the proximal spring portion 610 may also beshaped into a “V” shape. In certain embodiments, the V shape of theproximal spring portion 610 points toward the proximal direction. Thisallows the proximal spring portion 610 to collapse in situations where aexplantation is necessary.

Thus, when the assembly 600 is to be implanted, the distal springportion 608 can be inserted into a tubular insertion tool (not shown).The insertion of the spring portion 608 will pinch the arm members 624 aand 624 b as they enter the tubular insertion tool. The pinching willplace a compressive force on the members 624 a and 624 b, which willcause the members to move towards each other. In turn, the longitudinalmembers 604 and 606 will follow the movement of the arm members 624a-624 b and laterally compress towards each other. This compressionreduces the lateral profile of the assembly 600 which allows theassembly 600 to be inserted into an appropriate implantation tool. Whenthe assembly 600 exits the implantation tool, the spring portions 608and 610 are no longer subject to the compressive forces imposed by thetubular insertion tool and can expand to a predetermined distance. Theassembly 600 and the electrodes of the stimulation leads 502 a and 502 bmay then positioned within the epidural space in a manner that issimilar to an electrode spacing of a conventional paddle-style lead.

FIG. 7 a is a perspective view of another embodiment of an assembly orkit 700 using the stimulation leads 502 a and 502 b. The assembly 700may comprise a frame 702 having longitudinal channels 704 a and 704 bfor receiving the stimulation leads 502 a and 502 b, respectively.

In certain embodiments, the frame 702 may be formed from a solid pieceof a high durometer, biocompatible, biostable polymer, such as PEEK,PEKK, or LCP. The frame may be shaped with the longitudinal channels 704a and 704 b having interior diameters which allow the stimulation leads502 a and 502 b to be press fit into position. In certain embodiments,clip rings (not shown) may also be used to couple the stimulation leads502 a and 502 b to the frame 702.

In certain embodiments, the frame 702 may have a corrugated crosssectional shape or another shape which will facilitate bending orrolling when the frame 702 is subjected to compressive forces. Forinstance, FIG. 7 b is a detailed view of the end of the frame 702showing longitudinal corrugations 706, 708, 710, and 712 defined withinthe frame 702 which are designed to allow the frame to compress in apredicable manner when subject to lateral compression forces.

Thus, when the assembly 700 is to be implanted, the frame 702 may belaterally compressed or folded at the corrugations 706, 708, 710, and712. This compression reduces the lateral profile of the assembly 700which allows the assembly 700 to be inserted into an appropriateimplantation tool. When the assembly 700 exits the implantation tool,the frame 702 is no longer subject to the compressive forces imposed bythe tubular insertion tool and can expand as illustrated in FIG. 7. Theassembly 700 and the electrodes of the stimulation leads 502 a and 502 bmay then be positioned within the epidural space- in a manner that issimilar to an electrode spacing of a conventional paddle-style lead.

FIG. 8 a is an exemplary illustration of a proximal end 802 of a lead804 which could be used with any of the paddle ends or kits discussedabove. The lead 804 may have a structure or lead body 806 which has around or substantially round cross-section. Alternatively, thecross-section of the lead body 806 may be configured in any number ofcross-sectional shapes appropriate for a specific application in whichthe lead will be used. Depending on the particular application, thediameter of the lead body 806 may be any suitable size.

The lead body 806 may be formed of an extrusion or insulating materialtypically selected based upon biocompatibility, biostability anddurability for the particular application. The insulator material may besilicone, polyurethane, polyethylene, polyamide, polyvinylchloride,PTFE, EFTE, PFA, FEP, or other suitable materials known to those skilledin the art. Alloys or blends of these materials may also be formulatedto help control the relative flexibility, torqueability, and pushabilityof lead 804. In certain embodiments, the insulative material of leadbody 806 may be substantially composed of a compliant PURSIL® orCARBOSIL® silicone-urethane copolymer material. In some applications,compliant material characteristic enables the lead body 806 to elongatesignificant amounts at relatively low stretching forces. Additionaldescriptions of the insulative materials are described in co-pendingU.S. patent application Ser. No. 10/630,376 filed Jul. 29, 2003,entitled “System and Method for Providing A Medical Lead Body HavingConductors That Are Wound in Opposite Directions,” and U.S. patentapplication Ser. No. 10/630,233 filed Jul. 29, 2003, entitled “Systemand Method for. Providing A Medical Lead Body Having Dual ConductorLayers,” the contents of which are herein incorporated by reference intheir entirety for all purposes.

As described above in reference to FIGS. 1 a through 7 b, the distal end807 (FIG. 8 b) of the lead 804 includes a plurality of stimulationelectrodes 818 (FIG. 8 b). Adjacent to the proximal end 802 of lead 804may be a plurality of terminals, which in this embodiment, compriseseight connector or terminal electrodes 808. For purposes of illustrationonly, the lead 804 of FIG. 8 a is shown with eight terminals and one“dummy” terminal 809 on the end for assisting with connecting the leadto an implantable impulse generator. As will be appreciated by thoseskilled in the art, any number of conductors and electrodes may beutilized as desired to form lead 804. Generally, some embodiments havethe same number of stimulation electrodes as terminals. In thisillustrative embodiment, the terminals are shown as band or ringelectrodes.

In certain embodiments, both the stimulation electrodes and theterminals may be formed of biocompatible, conductive materials such asstainless steel, platinum, gold, silver, platinum-iridium, stainlesssteel, MP35N, or other conductive materials, metals or alloys known tothose skilled in the art. The size and shape of the electrodes aregenerally chosen based upon the desired application. In someembodiments, the terminals may be ring electrodes which encircleportions distal end. Other types, configurations and shapes ofelectrodes as discussed above or known to those skilled in the art maybe used with all embodiments disclosed herein.

One or more conductors 810 extending along a substantial portion of thelead body 806 electrically connects the terminals 808 to the respectivestimulation electrodes 818 (FIG. 8 b) which may be similar to theelectrodes discussed in reference to FIGS. 1 a-7 a. The conductors ofthe lead may be maintained in electrical isolation by the insulativematerial of the lead body 806.

In certain embodiments, the conductors 810 may be formed of a conductivematerial having desirable characteristics such as biocompatibility,corrosion resistance, flexibility, strength, low resistance, etc. Theconductors may take the form of solid wires, drawn-filled-tube (DFT),drawn-brazed-strand (DBS), stranded wires or cables, ribbon conductors,or other forms known or recognized to those skilled in the art. Thecomposition of the conductors may include aluminum, stainless steel,MP35N, platinum, gold, silver, copper, vanadium, alloys, or otherconductive materials or metals known to those of ordinary skill in theart. In some embodiments, the number, size, and composition of theconductors will depend on the particular application for the lead, aswell as the number of electrodes.

FIG. 8 b illustrates the lead 804 connected to an implantable pulsegenerator (IPG) 812 via a receptacle 814. Multiple leads may be coupledto IPG 812 if the header 816 of IPG 812 is so adapted. An example of acommercially available implantable pulse generator is the EON® pulsegenerator (available from St. Jude Medical Neuromodulation Division).Any of the preceding lead arrangements may be employed with IPG 812.

In this illustrative example, the lead 804 is connected to theimplantable pulse generator 812 via a receptacle 814 in a header 816.The lead 804 may be detached from the pulse generator 812 as desired byapplying a detaching force and removing the proximal end 802 (FIG. 8 a)of the lead 804 from the receptacle 814. Similarly, the lead 804 may beconnected to the pulse generator 812 by pushing the proximal end 802into the receptacle 814. A set screw or other locking mechanism (notshown) secures the lead 804 in place within the header 816 and preventsthe lead from being dislodged from receptacle 814.

When the system is assembled, the terminals 808 (FIG. 8 a) are inelectrical contact with electrical connectors (not shown) within theheader 816 of the pulse generator 812. A plurality of feedthrough wires(not shown) connect the electrical connectors to pulse generatingcircuitry (not shown) within the pulse generator 812. The pulsegenerator 812 sends electrical pulses to electrical connectors, whichare in electrical contact with the terminals 808. As previouslydiscussed, the terminals 808 are themselves in electrical contact withthe stimulation electrodes 818 at distal end 807 of lead 804 becauseconductors 810 (FIG. 8 a) electrically connect the terminals 808 to thestimulation electrodes.

Thus, the pulse generator 812 may generate and send electrical pulsesvia the lead 804 to the stimulation electrodes 818. In use, thestimulation electrodes 818 are placed at a stimulation site (not shown)within a body that is to receive electrical stimulation from theelectrical pulses. The stimulation site may be, for example, adjacent toone or more nerves in the central nervous system (e.g., spinal cord).The pulse generator 812 may be capable of controlling the electricalpulses by varying signal parameters (e.g., pulse amplitude, pulse width,pulse frequency, etc.) in response to control signals. In certainembodiments, the pulse generator 812 may programmed by or be incommunication with an external programming device (not shown) whichsupplies the control signals.

Although certain representative embodiments and advantages have beendescribed in detail, it should be understood that various changes,substitutions and alterations can be made herein without departing fromthe spirit and scope of the appended claims. Moreover, the scope of thepresent application is not intended to be limited to the particularembodiments of the process, machine, manufacture, composition of matter,means, methods and steps described in the specification. As one ofordinary skill in the art will readily appreciate when reading thepresent application, other processes, machines, manufacture,compositions of matter, means, methods, or steps, presently existing orlater to be developed that perform substantially the same function orachieve substantially the same result as the described embodiments maybe utilized. Accordingly, the appended claims are intended to includewithin their scope such processes, machines, manufacture, compositionsof matter, means, methods, or steps.

1. A paddle-style lead for implantation in the epidural space through aninsertion tool, the paddle-style lead comprising: a lead body; aplurality of conductors extending from a proximal portion of the leadbody to a distal portion of the lead body; a plurality of terminals thatare electrically coupled to the plurality of conductors; and a paddlestructure that comprises a frame of rigid material, the frame comprisingfirst, second, and third longitudinal members in a planar configuration,a distal linking portion that is mechanically coupled to the first,second, and third longitudinal members, and a proximal linking portionthat is mechanically coupled to the first, second, and thirdlongitudinal members; wherein a respective plurality of electrodes areprovided for each of the first, second, and third longitudinal members,each plurality of electrodes being electrically coupled to conductors ofthe plurality of conductors; wherein the distal and proximal linkingportions are adapted to permit compression of the first and thirdlongitudinal members toward each other and to permit the secondlongitudinal member to move out of plane relative to the first and thirdlongitudinal members when a compressive force is applied to the paddle.2. The paddle-style lead of claim 1 wherein the distal and proximallinking portions provide a spring-force to restore the first, second,and third longitudinal members to the planar configuration after removalof compressive forces upon the paddle.
 3. The paddle-style lead of claim1 wherein the second longitudinal member comprises a plurality ofcolumns of electrodes along a length of the second longitudinal member.4. The paddle-style lead of claim 1 wherein the first, second, and thirdlongitudinal members are fabricated using a rigid polymer selected fromthe group consisting of PEEK, PEKK, and LCP.
 5. The paddle-style lead ofclaim 1 wherein the plurality of electrodes of the first, second, andthird longitudinal members are deposited on rigid insulative material ofthe first, second, and third longitudinal members.
 6. The paddle-stylelead of claim 1 wherein the plurality of electrodes of the first,second, and third longitudinal members are disposed on an intermediatepolymer later that is laminated to a thicker substrate layer.
 7. Thepaddle-style lead of claim 1 wherein electrical connectors are embeddedwithin the first, second, and third longitudinal members and theelectrical connectors are electrically coupled to the plurality ofelectrodes through vias in insulative material.
 8. The paddle-style leadof claim 1 wherein the plurality of electrodes of the first, second, andthird longitudinal members are provided on one or more flex-circuitsthat are laminated to rigid insulative material of the first, second,and third longitudinal members.
 9. The paddle-style lead of claim 1wherein the distal linking portion provides a spring force to the paddleto bias the first, second, and third longitudinal members in a planarconfiguration.
 10. The paddle-style lead of claim 1 wherein the proximallinking portion provides a spring force to the paddle to bias the first,second, and third longitudinal members in a planar configuration.
 11. Amethod of fabricating a paddle-style lead for implantation in theepidural space through an insertion tool, the method comprising:providing a lead body with a plurality of conductors extending from aproximal portion of the lead body to a distal portion of the lead body;forming a paddle structure comprising a frame of rigid material, theframe comprising first, second, and third longitudinal members in aplanar configuration, a distal linking portion that is mechanicallycoupled to the first, second, and third longitudinal members, and aproximal linking portion that is mechanically coupled to the first,second, and third longitudinal members, wherein the distal and proximallinking portions are adapted to permit compression of the first andthird longitudinal members toward each other and to permit the secondlongitudinal member to move out of plane relative to the first and thirdlongitudinal members when a compressive force is applied to the paddle;providing a respective plurality of electrodes for each of the first,second, and third longitudinal members; and electrically coupling eachplurality of electrodes to conductors of the plurality of conductors.12. The method of claim 11 wherein the distal and proximal linkingportions provide a spring-force to restore the first, second, and thirdlongitudinal members to the planar configuration after removal ofcompressive forces upon the paddle.
 13. The method of claim 11 whereinthe second longitudinal member comprises a plurality of columns ofelectrodes along a length of the second longitudinal member.
 14. Themethod of claim 11 wherein the first, second, and third longitudinalmembers are fabricated using a rigid polymer selected from the groupconsisting of PEEK, PEKK, and LCP.
 15. The method of claim 11 whereinthe plurality of electrodes of the first, second, and third longitudinalmembers are deposited on rigid insulative material of the first, second,and third longitudinal members.
 16. The method of claim 11 wherein theplurality of electrodes of the first, second, and third longitudinalmembers are disposed on an intermediate polymer later that is laminatedto a thicker substrate layer.
 17. The method of claim 11 whereinelectrical connectors are embedded within the first, second, and thirdlongitudinal members and the electrical connectors are electricallycoupled to the plurality of electrodes through vias in insulativematerial.
 18. The method of claim 11 wherein the plurality of electrodesof the first, second, and third longitudinal members are provided on oneor more flex-circuits that are laminated to rigid insulative material ofthe first, second, and third longitudinal members.
 19. The method ofclaim 11 wherein the distal linking portion provides a spring force tothe paddle to bias the first, second, and third longitudinal members ina planar configuration.
 20. The method of claim 11 wherein the proximallinking portion provides a spring force to the paddle to bias the first,second, and third longitudinal members in a planar configuration.